System and method for iron casting to increase casting volumes

Abstract

A system for casting pig iron is provided. The system has a runner, a tundish, and a mold receiving molten iron in a superheated state, and a feed system positioned adjacent to one of the runner, the tundish, and the mold. The feed system contains solid particles having a chemical composition substantially similar to the molten iron, and is positioned to direct a stream of the solid particles the one of the runner, the tundish, and the mold such that the stream of solid particles mixes with the molten iron. A method is also provided. A stream of molten metal is provided in a superheated state during a casting process, and is mixed with a stream of solid particles such that the solid particles at least partially melt with molten metal to increase a volume of the molten metal without substantially changing a chemical composition of the molten metal.

What is claimed is: 
     
         1 . A system for casting pig iron, the system comprising:
 a runner receiving molten iron in a superheated state;   a tundish receiving the superheated molten iron from the runner;   a mold positioned beneath the tundish to receive superheated molten iron therefrom; and   a feed system positioned adjacent to one of the runner, the tundish, and the mold, the feed system containing solid particles having a chemical composition substantially similar to the molten iron, wherein the feed system is positioned to direct a stream of the solid particles the one of the runner, the tundish, and the mold such that the stream of solid particles mixes with the molten iron.   
     
     
         2 . The system of  claim 1  wherein the solid particles comprise iron-rich material from iron-making and steel-making slag fines. 
     
     
         3 . The system of  claim 1  further comprising a controller in communication with the feed system to control a feed rate of the stream of solid particles. 
     
     
         4 . The system of  claim 3  wherein the feed rate is set to maintain the molten iron in a superheated state after the stream of solid particles is added by the feed system. 
     
     
         5 . The system of  claim 1  wherein the mold is supported by a conveyor on a pig iron casting machine. 
     
     
         6 . The system of  claim 5  further comprising a water spray system to cool the mold on the conveyor. 
     
     
         7 . The system of  claim 1  wherein the feed system comprises an auger feeder. 
     
     
         8 . The system of  claim 1  wherein the feed system comprises a vibrating feeder. 
     
     
         9 . The system of  claim 1  wherein the feed system comprises a heater to preheat the stream of solid particles. 
     
     
         10 . The system of  claim 9  wherein the heater comprises a torch, the torch oriented countercurrent to the stream of the solid particles. 
     
     
         11 . A method comprising:
 providing a stream of molten metal in a superheated state during a casting process;   providing a stream of solid particles; and   mixing the solid particles with the stream of molten metal such that the solid particles at least partially melt with molten metal to increase a volume of the molten metal without substantially changing a chemical composition of the molten metal.   
     
     
         12 . The method of  claim 11  wherein the molten metal comprises molten iron; and
 wherein the solid particles have a chemical composition substantially similar to the molten iron. 
 
     
     
         13 . The method of  claim 12  wherein the solid particles comprise iron-rich material from iron-making and steel-making slag fines. 
     
     
         14 . The method of  claim 13  further comprising subjecting the slag fines to a series of classification steps which progressively sort the slag fines by various physical properties of the material, including magnetism, size, and density, into relatively iron-rich and relatively iron-poor classifications, wherein at least one of the classification steps includes introducing the slag fines as a slurry into a non-compressible fluid fluidized bed separator to separate relatively lower density and relatively higher density constituents of the slag fine particles suspended within the fluidized bed. 
     
     
         15 . The method of  claim 11  further comprising cooling the mixture of particles and molten iron in a mold to form a casting. 
     
     
         16 . The method of  claim 15  further comprising water cooling the mold. 
     
     
         17 . The method of  claim 11  wherein the stream of molten metal remains in a superheated state after being mixed with the solid particles. 
     
     
         18 . The method of  claim 11  further comprising heating the solid particles prior to mixing the solid particles with the stream of molten metal. 
     
     
         19 . The method of  claim 18  wherein the solid particles are heated to at least five hundred degrees Fahrenheit. 
     
     
         20 . The method of  claim 11  mixing the solid particles with the stream of molten metal further comprises mixing the stream of solid particles into the molten metal in a runner and/or a tundish. 
     
     
         21 . The method of  claim 11  wherein mixing the solid particles with the stream of molten metal further comprises providing the stream of solid particles into a mold prior to pouring the stream of molten metal into the mold. 
     
     
         22 . The method of  claim 11  wherein the molten metal has a first chemical composition; and
 wherein the solid particles have a second chemical composition that is substantially similar to the first chemical composition.